Each day a different image or photograph is featured, with an
accompanying caption, which deals with various topics in Earth Science.

Ice Donuts

August 28, 2008

Provided and Copyright by: Tim WenzelSummary Author: Tim Wenzel

These "ice donuts" are a common sight in river channels, during late winter, near South Haven, Michigan. Their origin isn’t completely understood, but they may form when wind and wave action begins to disintegrate the icy surface, once the ice has already been fractured into meter-sized polygons. In very cold and windy weather, wave splashing tends to freeze on top of the ice edges, creating ridges. The higher the ridge, the more it’s exposed to the cold wind, and further splashing builds the ridge even higher. Photo taken on March 8, 2008.